Preselecting and shifting device for transmissions



June l J. BLACKBURN PRESELECTING AND SHIP-Tmc DEVICE FOR .TRANsMrssIoNs Filed June 5 0. 1924 4 Smeets-sheet 1 TTY.

June 1 ,1926. 1,586,515I

J. BLACKBURN PRESELECTING AND SHIFTLNG DEVICE PoR TRANsMIssxoNs l Filed June- 5o. 1924 4 sheets-sheet 2 fia. Z

June 1926.

J. BLACKBURN PRESELECTING AND SHIFTTNG DEv'cE FOR TRANSMISSIONS 4 sheets-sleet s Filed June 3Q, 1924.

J. BLACKBURN June l 1926. A I 1,586,515

PIVSELEC'I'ICT` AND SHIFTING DEVICE FOR TRANSMISVSONS Filed June ISO, 1924 4 Sheets-Sheet 4 Patented June l', `1.926.

- UNIT PArsur eprice.; i

JASPER BLAcKBUnNgor 'Winasrnn..cfnovn'sJ MISSOURI.

Punset-norme; AND sHIrTING nnvron non TRANsMI'ssIoNs.

, 'Application meaning 30.1924, 'semaine-.723,181 i Y i My invention relates to improvements preselecting and shiftingdevices for transmissions and has for. its primary `object a device for motor vehicles in which varlous speeds can be preselected andthe actualy shifting of gears accomplishedregardlessof vehicle or motor speed:-

A fiuther object is to construct a preselect n* lng and shifting devicev for transmissions 1n' -ivhiclr it is li'ossiloleV to shift `toone speed rand immediately thereaterpreselect a second speed Without starting the' vehiclerat all. y

and ready for another preselection Yassoon' as the shifting o'fthevfirst selection has been accomplished. n

In the drawings Fig. 1 is a fragmentaltop plan vieiv V'of motor .vehicle .chassis showing my device attached thereto; F ig. Q is an enlarged longitudinal vertical section fof the transmission housing withV the preselecting` and. shittingl device attached thereto;

Fig. 3--3 of Fig. 2; w f F ig; 4' is. a top plan viei'v of the vpreselecting and shifting mechanism with the cover removed;

Fig. is a rear view of shifting mechanism `removed from the transmissionhousing; f 3. Fig; 6 is affrontr elevation of the same;

Fig. 7' is a side elevation of the same showingithe manner in' which the slide operates thel rear clutch member;

Fig. 8 is a front elevation of Vthe gear shifting and preselecting mechanism 'showingl the same attached Yto lthe foot selector; y Fig.V 9 is a fragmentalfse'cltional *view of the slide har showingthe manner of attach- "y ing thefoot selector thereto: y K y' g of the pedalv VVFig. 10 is a top plan vieuY use'don the foot selector; f

Fig. 11 is anenlar'ged top plan vien7 the 'floor plate madeuse of;v i Fig. 12 is an enlarged fragmental section of the connecting bar; l

Fig. 13 is an enlarged perspective view of the lever support; f c n x Fig. 14A is an enlarged slde'elevation yof one ofthe preselecting drums; n c i Fig. 15 is an end view of the same; Y

` nism 8 is a cross sectiontaken onthek line" the preselectingand ing elements;

F 1g. 17 is an edge vien7 othe sameg.

hars

of the'top showing the lock employed to/prevent accidental movement of one'ro'f the Shifting elements i ,i s

Fig.- 20 is ka' fragmental sectional view elements infposition;k f

215is a' similar view showing `,the locking means .released preparatory to moving one `ofthe `shiftiiig elements; and

f Fig. 22' is" a kperspective View of the' latch employedor operatingthe shifting mechaout operatingT ythe Apreselecting means.

videdwvith a :crank shaft 24, on'one end of which isy secured a fly' Wheel25. Secured to thechassisjframe in any -Well known manner,

kis a transmission:housingQfWhichhas profjecting from its'forward' enda driven-shaftv Zouwhich 'is slidably mounted a clutch 28,` .this clutch having engagement with aclutch `member formed either integral With they Wheel 25 or'mounte'd adjacent thereto on the engine shaft' 24. `The clutch member 28is `operated by the usual clutch' collar 29iand footlever 30. Projecting from the rear of 1 the transmission housing T26. is a driving "shaft 31,'r to .this drivingshaft is ttacheda *universal joint, which in turn' is. connected to the rpropellershaftY leading tothe" rear Fig. isaV face lview-of one of the slide o .Y

Fig. `19,` a rragmentaliibottom plan View v Q3 is a'ffragmental vieW showing the Vstop employed. for 'shifting to neutral With,`

shoivingtlie manner of locking the shiftingA axle. ,Thisv universal joint and .propeller `r yshaft-,being oldfwvill not he "shown or'de- 'scribed indetail. "Formed integral with the driven-shaftQfisfafgear 82,` thisfgear is locatedfinsideo the housing 26 and meshes with a gear carriedby the counter-'shaft Mounted on y,the ;coimterlshaft` 34 are vgears 35 and 36 which `are respectively second yandflirst speed. Meshing Withthe gear 36 isagear'pwhichris mounted on a shaft '38;' On the shaft 38 fisalso locatedk the gear 39, the gears 37. andf39 constituting the reverse jdrive. :The gearyBQ is provided with a centralopening invvhichthe end y40 ot a splined shaft i14 is mounted, the" opposite n end 42of-this'shaft heingniountedjin the Cil driving shaft 31. Slidably mounted on the shaft 41 are gears 43 and 44, the gear 43 is provided with a forwardly projecting portion 45 which is adapted to iit over the gear 32 and constitutes the high speed. The gear 43 is adapted to mesh with the'gear 35 for second speed and the gear 44 to mesh with either the gear 36 or the gear 39. for first speed and reverse. v

Carried by the shaft 31 and within the casing 26 is the member 46 of a clutch. The complementary vmember 47 of this clutch is slidably mounted on the shaft 41, the member 47 is provided with a grooved collar 43 into whichV a fork 49 passes. The forl 49 is carried by the member 50 which is secured tov a shaftJ 51, the shaft 51 being slidably mounted in the housing 26. The member 50 is-provided with recesses 51a vand 52 into which one end ofV a pawl 53 is adapted to iit, the opposite end of theV pawl 53 is provided Awith a right angular extension 54 which is beveled as at 55. The purpose of this pawl will be explained in detail later. The pawl isactuated by means of Va spring 56'. The shaft 51 is provided with a notch or recess 57, the purpose of which will be explained in detail later. The shaft is also provided with a bore 53 in which one end of a coil spring 59 is seated, the opposite end of this spring bearing against Ythe front wall of the transmission housing 26. The purpose of this spring is to normally `hold the clutch membersY 46 and 47 in engagement. he contacting faces of the clutch'members 46 and 47 are provided with radially extending grooves 60 which permit oil to be squeezed `out from between the'members and permitting ready engagement 0f the clutch. The

clutch as shown, has the member 47 provided with projecting pins 61 which are adapted to enter suitable recesses'or pockets formed-in the clutch member 46. Mounted on top of the housing 26 is a housing having a front wall 62, a rear wall 63, side walls 64 and aroundits lower edge-a flange 65, the front and rear walls 62 and 63 are providedwith slots 66 and 67.` In the slots 66 are located the .ends 63` of the slide bars 69 Adjacent the ends 63 the bars are made wider, as at 70 forming shoulders 71v and 72. The shoulders 71 are adapted to abut' against the inside of the end walls 62 and 63 and prevent the bars from shifting, while the shoulders 72 are adapted to come in contact with the slide 73 ofthe shifting elements. The slide 73 ofthe shifting elements is provided with a groove 74 which is adapted'to receive that part of the slide bar between the shoulders l72.` The slide 73 has its rear face 75v in contact with the side walls 64. The slide 73 is also provided with cylindrical openings 76. The opening at the inside face 'of the slide being slightly reduced (See Figs. 16 and 17 so as to pre- `to which a ball 32, located in the opening 33 in the slide bars 69, is adapted to pass. The purpose of this will be explained in Ydetail later. The slide bars are provided with forks 34 and 35, the fork 34 operating the second and high speed gear, and the fork 35 the first and reverse.`

Mounted in the VslotsV 67 are bars 36 and 37, these bars are provided on one end with teeth 33, these teeth are located opposite each other and are designed to mesh with a gear 39 carried by the front wall 62 and are for the purpose of causing the bars 36 and 37 to travel in opposite directions simultaneously. The bar 37 projects rearwardly from the wall 63 and is provided on its end with a lug` 90. rllhis bar has also attached to its projecting end a coil spring 91, the purpose of which is to normally hold the bar 37 and consequently the bar 36 .in the position indicated in Fig. 4. rlfhe bars 36 and f 37 are also provided with` projections 92, one face of which is inclined as at 93. These projections are adapted to Contact with the balls 32 and force them into one of the recesses 79, 30 or 31 and prevent accidental shifting Yorsl'iding of the shifting elements, and also at the same time release the balls from the recesses in the shifting elements when the bars 36'and 37 are moved. Carried by the bars 36 and 37 are forks 94 andY respectively, these forks are in turn connected'respectively to shifting drums 96 and 97. rlhese drums are slidably mounted on a shaft 93. The drums 96 and 97 while being slidably mounted on the shaft 93 are still so secured thereto that they cannot hc rotated independently of the shaft and for this purpose a square` shaft is preferably used. The forward end of the shaft 93 projects through the front wall 62 and has scl cured on its end a gear 99 whiclrmeshes vwith a gear 100, this gear is also carried bythe front wall. Meshing with the gear 100 is a segment 102 which is provided with an arm 103. The arm 103 is pivotally connected to a link 104, the opposite end of this link being in turn pivotally connected to a slide bar 105. The slide bar 105 is supported in brackets 106 carried by a plate 107, this plate may be either attached to the floor board of a motor vehicle or it may be attached to any suitable place either on the vehicle or some portion of the transmission housing. This however, is optional with the builder and depends a great deal Vactuated'ball 109 isllocated. y is adaptedV to .enter recesses 1104 formed in the face of the plate 107 adjacent the slide on the amount of .space avail-able between the floor board and` the'` transmissionhousing. The slide bar 105 'is' ^`alsofprovided with arecess or bore 108 in whicha spring The ballV 109 bar and is to prevent any accidentalsliding of the kbar 105 due to .road shocks.

105 is the foot selectorwhich consists-of a bar111 which projects .forward through the floor 112, and. also through thefloorf plate 113. The floorqplate 113 lis lprovided with a groove ,114, .theycentral portion of' which isA offset, asillustrated in Fig-.111.. The purpose of v.this offset: is to provide ak shoulderY against which' vthe bar 111 can strike during the ipreselecting.` so that the movement of theslidebarand the foot selectoris'limited between two speeds and it will be impossible for the operator to accidental# ly shift .from a reverse'to high speed or Avice versa, or in fact to' accidentally skip ay Speed. f f Y f My device is so arranged that points midway between reverse an'dfirst, first and sec-f ond, and second and'third'causes the trans missiontobe preselectedvforV neutral. f `In this way I have threepoints from which my device can be set intopneutral and thus ak great `deal of foot manipulation is elim'i-Lv nated. y y

The bar 111 is forced towardthe operator by meansof a coil spring 115 and is l pro videdon its upperken'd wi-thl a T shaped'.

pedal 116. My purpose off making kthe pedal T shaped is that the.` twowings of the T permity the .foot to readily. press `tlie'b'arlll forward, while the'legv of the Tpermits the foot toreadily move thev lever or slide bar4 to the right or leftas the case may be.l

.Mounted against'the iwallll adjacentthe Y this pin is adapted tov come `in contact with the inclinedfa-ees 123of the bifurcated latch -puller12et and release the latch'from the lug 90. f The slide is retained in posit-ion by ineansof a `rib 125 which is formedintegral with the {iange and spaced apartffromy the" wall 64 againstV which thek slide 117,;

Located vertically in the slide-is a0 KK y14C1of the lever 140 when the main clutch is rests. v springfa'ctuated pawl 1.26', thispawl is retained in position within the slide by'ineansp.

of a vslottedf'plate 127. -The pawl 126 is provided with Va pin, 128 Vwhich extends,`

through they slot in the plate and adapted toj come. in contact-with the inclined lug 129carried by therib 125, the purpose of PivaL otally carried by thel free end of the bark The latch hasv also thislug andgllatch will be enplainediin detail later; f l i yIt will be `noted that the ends 62' and G3 are lowerthanx thesides' and in order to "make vup.this'deficiencyafter the parts have beeny assembled in the, housing, filler plates 130are employed. Over ytheser filler plates 'and sides 64; is placed a cover 131.,A this cover is also ofsuiicient width to; extendover the slide 117 and ,preventy its being- V`lifted or.be ing jolted out offposition.y It is to be under-- stood of course, that "the flange ,65 is pro'- videdjwith al slot' 132 through which the pawl or latch 126' passes, the purpose of this slot will be.e`k\*pla'inedr in detail later.

`- The slideso-n the shifting elements arepro.-

vi'dedon their. inner faces and adj acenttheir top Iedges" with-recesses or` notches" 133, these notches are designed'to 'receive `the ends 134 fof the lock .135"whieh is slidablylocated in a j housing 136.,.sejcured to theunderside of vthe f soy c cover 131.1.' It `.willbe.noted from Fig. 19

that thelock 135 lis longer than .the distance between the insideffacesof the slides 73, the purpose'of thisis..-tha't Va'ssoon asione/ slide yisrinoved, the Vrlo'ckis` forcedinto the recess 'ofthe opposite slide thus holding it in p'osi- 'K tiony and againstv 'accidental inovementjb'ecause there.1snofother` way 1n which this `slide can bethus 'held,as during the shifting `the balls 82 "are releasedfrom both of the slides. -Tl1e-ends413llofthe lock'135 however, cannotenter therecessof the slideV unvless that shiftingvelement is vin'neutral [posi-A tion;y in 3otherwords`, whenv the gear con,r

trolledjby thatparticulary slide is midway between the two gears with which it is designed to mesh. f .y v I y f Secured` to therear end ofthe slidef117y is an L 'shaped bracket 137 which is provided withaneye: 138Vtorwhich a spring` 139 is seV cured, theopposite end of the spring' 139, as well as theend of the springk 91 being senk cured to any suitable port-ion ofr the vehicle frame..` A vCarried by the chassis frame 23 is a pivotl ed leverlO, its free end 141 isfadapted to come in `contact with the bracket 137 and move the slide forward. yThe. lever 1ei0i,s connected to the clutch pedal 30fbymeans ofalink 1%12fandin order'to prevent excessivevibration of the lever 140 the saine is mounted in thebifurcation 11-3jof the lever fsupport ,1441. This lever support may beatin engagement is positioned at some distance allow the drivingclut'ch 28 to be disengaged 'before the levercontactswith theslide 1-17 and commences the' shifting operation. J

The operation of'my deviceis as follows-f.

to the ,reary `ofthe bracket 137. `Thisisto Y iso f I .will start describing the operation presuming the machine to be in the garage and ready to back out, after the engine has been started the bar 111 is movedv so that it oc-- cupies the position in the slot 114 in the floor plate marked R. This movement rotates the shaft 98 and brings the point 145 on the preselecting drum. 96 in alinement with the slide adjacent the bar 86. This movement also brings the groove 146 of the preselecting drum 97 in alineinent with the balls 77 carried by the same slide. A forward movement of the clutch pedal iirst disengages the clutch 28. As soon as the clutch 28 has been disengaged the end 141 of the lever 140 comesV in Contact with the bracket 137 and commences to move the slide 117 and during this time the lat-ch 118 is in contact with the lug 90 and the pawl 126 is located in the notch 57, while the pawl 53 is at rest in the notch or recess 51a. A continued depression o1 the clutch lever now carries back the bar 51, as well as pushing forward on the bar 87, this forward pushing on the bar 87 in turn rcauses the bar 86 to move backward. This movement causes the preselecting drums to move toward each other simultaneously. The movement of the shaft 51 continues until the latch 53 drops inrothe recess 52 at which time the clutch members 46 and 47 are completely disengaged. At the inonjient the pawl 53 enters the recess. 52 the pin 128 Vrides up on the lug 129 and raises the'pawl 126 out of the notch 57, the pawl 53 now holding the clutch members 46 and point or projection 145 comes in` contact with the slide carrying the fork 85 and commences to push it backward. The movement of t-he bars 86 and 87 have also released the balls 82 which vhave heretofore been seated in the recess 80 of the slide. A continued depression of the clutch pedal now commences toY shift the slide which carries the fork 85 and in so doing forces one of the ends 134 of the lock 135 into the recess 133 of the slide which carries t-he fork 84. A Continued forward movement now com# mences to shift the gears. At this point one of the balls 77 carried by the moving slide rides out of the recess 78 formed in the side walls 64'and project-s vinwardly from the slide, as illustrated in Fig.. 3, but is pre-ventedl from contacting with the preselecting ldrum on account ofthe slot 146 being in alinement with the ball. A continued move ment causes the gears to commence tomcsh, as soon as the gears have partially meshed, the lug 90` comes in contact'withthe inclined face 55 of the vright angular extension 54 of the pawl 53 and raises the pawl 53 out of the notch or recess 52 thus releasing the latch 57 and permitting the spring 59 to force it backward. and i:e-engage. the clutch members 46 and 47.

.At the time when the shifting of the gear 44 into the gear has been completed the pin 122 lhas ridden up the inclined surface r123 `and withdrawn the latch 118 permitting Y139 pulls the slide 117 backward to its original or starting position. The latch by reason of its inclined face and the leaf spring 121 rides past the lug 90 and is again in position to again commence shifting. All of this however, takes place prior to the final moi/'ement of engaging the clutch 28 and furthe-r letting in of the clutch carries the end 141 and lever 140 clear of the bracket 137. A slight depression of the clutch pedal will now merely disengage the clutch without shifting the gears, this is essential because the operator may rdesire to bring Vthe car to a .stop or to proceed ina rearward direction. VAfter the car has been backed tout of the garage, it is only necessary to again depress the clutch pedalto its fullest extent and the transmission will be shifted to lirst or forward' speed.l and while the clutch pedal is still depressed.` second speed can be preselected and ready for shifting upon depressing the clutch again.

In the saine manner a ter having arrived at high speed I can set my device either for second speed, first speed or neutral according to trariic conditions encountered, and thus it will not be necessary for the driver to make sudden decisions and possibly forget to shift gears after coming to a halt in tratiic, as this can all be done at times when the drivers mind is at rest and not be confused or excited by congested traiiic conditions.

Then my device has been shifted to a preselected speed by the movement of the slide 73 one of the balls 77 has been forced past the recess 78 so that it projects from the face of the slide, as illustrated in Fig. 3. Thenv as the preselect-or is shifted to any of the neutral positions the shifting Sleeves 97 and 98 are .so turned that neither the projection 145 nor the recess 146 is in alinement with the slide or ball. Then upon depressing'the clutch pedal and operating the shifter bars 86 and 87, the inner face of one of the preselecting drums will contact with the ball 77 and force the slide toward the center. This movement continues until the ball 77 drops into the recess 78 which disfrom the preselecting drum with which itis iii `Contact land'spermits the drum t0; ridefpast. i v Y Y `In 1 Fig. 23 `l means of .shifting the transmission into neu# tral Without operating the` preselectingf4 lever. I nrtliis instance, I mount on the toe board `l5() of the vehicle, a stop 151, this stop is -adjaceiitlthe clutch pedal 130V and is oi' a. sutlicient heightv topermit lthe pedal toY` be depressed only halt way, and indepressf ing the pedal haiiu way the slide- 73, designed to be operated according. tothe preselection,

is moved. only halfvvvay Vor toneutral posi-jV tion. In giitilizing'thestop. 151 it isnecessary to place the footk on Lthe clutch pedal in such-a manner that alportion of thejshoe` sole projects beyond fthe side of the ypedal c and comes iiicontact- With the stop, thus' f ei'fectually preventing complete depression. ofthe clutch pedal and consequently"cans-MA ingon'ly the-tirsthalr" of the shi-ftto .be completed, and that halt` :being the movement of the' shifted gearto a neutral p ol f f ing gearsa rclutcliunonnted lon .the driven sition. Y

i It will further be notedthat the rearwardV movement of the slide 1 17 is V*limited `bythe slotf132 formed inthe v flange 65, the rear edge of this slot being so arranged that the*y latchor pavvl 126 abuts against `its endand limit-.s further rrear movement ofthe slide, the 'forward inovenient off the slide controlled by the clutch pedal.`

In the eventthat theV transmission `.lions-iy ing lis set closev under the 'floor boards, I may dispensevwith; the gear- 100 and quadrant F102 and .use a rack meshing With the gear 1 In a preselecting and shifting device transmissions, 1 comprising a casing,

for gears,gsome ofwhich are slidably located in said casingfa clutch Vlocated at .each end of said casing, a preselecting mechanism lol cated vvithiiiithe casing, means operableby the preselectiig mechanism foishifting'the slidingV gears, means for diseng'aging said clutches, means for permittiiigone of said clutches tot 4be reengaged While 'the other clutch is being further.,disengaged, :means for operating the preselecting mechanism for Apreselecting ay predetermined speed,

ineansoperated by the clutchdisengaging means and connected to the preselecting means for shifting said transmission to the preselected speed, and means whereby saidk preselecting V and shifting mechanism is au-r ing said clutchivhen theshift is partially toinatically returned to its starting position When-the shift has been made. c 2. A preselectingland shifting device for transmissions comprising a transmissiona completed and before the clutch on' the driven end has been reengagedI housing, a sliding geartransinission located therein, a clutch located Without said housmeans" 4ifor ,.'disengaging the second kmen` r10eme "i clutch has beenjdiseiigagedand for 'operat-y Thefrack, 'inthis instance, would be connected to the slide bar 105 by means off leetingmeans to `startingnpositionwhenithe ingandk at the drilven end thereof, fa second c f v clutch located' at the Adriving endof said' have illustrated another transmission, shaftLloca-tediin!v said housing, preselecting drums slidably-.secured oni saidy yshaft andfrotatable .tlier,eivitli',fmeans `for rotating said shaft, means `for nmoving.

pieselecting and shifting deviceffor' -said'piteselecting drums `tovvard*each'other, c simultaneoiisly,` means co-acting With .said

transmissionscoinprisiiiga housing, a plui'alityfgof gears rotatably mounted in said' housing, a plurality of. gears slidablymorunt-g.

ing shaft "adapted to lbe driven by the. slidsha'ft, a second clutchfmounted Ion .the 'drivingshafgfa preselecting means `for preselect ing one y.ofthe sliding gears, means forvoperating `the clutchl on `the fdriven shaft, means connected to"-'saicl:-clutc h .operating tionedy clutchv after the first mentioned ngfthe .p reselecting Vmeans `thereby shifting *,tlie'preselectedf geaimafter ysaid disconnec@A tion has Sheen made, means for automatically re-,engagingk otithesecond mentioned, clutch ed in saidhousing, -a driven -,shaft vfor vplacfing sometofsaid gears rin rotation, va "driv-L so'Y when the-'shifting has 'beentpartiallyjConil.

pleted, andfmeans for -returning the prese? shifting' :has been completed `'and before 'the f clutch` ,onf the ,driven/f shaft has 'been' ref eiigag ed. f L 4; Apieselecting-.and shifting device ,for

transmissions [comprising in combination with .a casingy vcontaininga `plurality yofi gears, some of which are slidably .mount-ed,

and afoot-operated preselecting mechanism, said transmissionliaving a clutch'located at' f `its driven endaand-a secondfclutch at its driving end, meansv forA diseiigaging :said i clutches kin sequence, means operatedby Ithe clutch -.disengaging meansfor operating the '1,

preselecting niechanisinyitor shifting tofai `preselected gear,`l;;me ans for .holding the clutch at the driving end out of engagement during the; initial portion of the shift, .means adapted to kbe released during the movement #ot the preselecting mechanism operating rmeans for automatically reengagcompleted, and means foi' returning the Lpielselec'tingand shifting mechanism to its starting position when the `shift has been iso 5.y A preselecting and shifting device for transmissions comprising a sliding gear transmission. and 1ts casing, a clutch located at the driven end thereof, a secondclutch lo- 4cated at. its driving end, shifting elements speed without first re-engagin'g the firstV mentioned clutch. v

6. A preselecting Vand shifting device for transmissions comprising a sliding gear transmission, shifting elements for operating said sliding gears, a preselecting and shifting mechanism for operating the shifting elements, means for operating said preselecting and shifting mechanism, means for returning the preselecting mechanism to its startingposition whereby, a second selection may be made immediately after the first selection has been completed and without placing the transmission in operation,

and means whereby the movement of the.

preselecting shifting mechanism operating means is limited .and vsaid preselecting and shifting mechanism is lonly partially operated whereby said transmission is returned to neutral position without changing the setting of the preselecting and. shifting mechanism.

.7. A preselecting and shifting device for transmissions comprising in combination with a casing containing a plurality of gears, some -ofwhich are slidably mounted, and a preselecting mechanism, said transmision having a clutch located at its driven end, and a second clutch at'its driving end, means for disconnecting said clutches in sequence, means carried by the casing for holding the clutch at the driving end out of engagement during the initial portion'of the shift, means for automatically releasing said holding means whereby said clutch is re-engaged when the shift is partially completed,

means for automatically returning the shifting preselecting mechanism to its starting position when the shift has been completed and before the clutch on the driven end has beenV re-engaged, and means located adjacent the clutch disconnecting means whereby the movement of said clutch disconnecting means is limited and the shifting mechanism only operated partially, whereby said transmission may be returned to neutral position without changing the preselecting means.

8. A'preselecting and shifting device comprising'a sliding gear transmission and its housing, shifting elements slidably mounted in said housing for operatingsaid sliding gear of said transmission, means for holding said shifting elements against movement before and after shifting, means for holding one of said elements against movement during the movement of the other element, a pair of preselecting drums capable of. rotary movement and of movement simultaneously to and from each other located in said housing adjacent the shifting elements, foot operated means for rotating sai'ci drums so that one thereof may be brought incontact with a preselected shifting element and move it inthe desired direction, a clutch located at the driven end of said transmission, a second clutch located at its driving end, a clutch pedal for disconnecting said clutches in sequence, means for returning the second mentioned clutch and the preselecting drums to their original position while the first mentioned clutch is still disengaged whereby a second preselection can be made before reengaging the `rst mentioned clutch, and means for limiting the movement of the clutch pedal whereby said transmission may bershifted to neutral after a preselection has been made without changing said preselection.

9. The. preselecting and shifting device of claim 5 in which a stop is located adjacent the clutch and drum operating means for limiting the movement of said drum' operating means, whereby the transmission may be shifted to neutral when shifting from one speed to another without changing the preselection.

ln testimony whereof, I have signed my name to this specification.

JASPER BLACKBURN. 

